For human health, as well as human comfort, it is desirable to provide a sun shade above many outdoor living and recreational areas. Such areas include the porches of apartments and condominiums, decks, areas near swimming pools, outdoor restaurants, and other outdoor commercial areas. In warm seasons and in warm climates, on cloudless days, the bright sunlight can make an outdoor area extremely uncomfortable or uninhabitable, particularly where the area has a southern or western exposure. Although trees and other vegetation can provide natural shade, in many areas, particularly areas of recent construction, such vegetation is too small to provide practical shade.
There are a variety of products readily available which attempt to solve this problem. Most, however, are expensive because they include sophisticated mechanisms to enable them to be completely retracted for providing overhead exposure on non-sunny days. The sophisticated mechanical mechanisms typically require precise alignment and adjustment, and require expensive maintenance if they become misaligned. Most prior art overhead shading structures have only a limited or no ability to permit the user to fully or only partially retract selected portions in order to tailor the shaded area to the user's needs at a specific time of day and sun position. Some prior art structures require that a contractor be employed to construct a wooden overhead support structure. There are also considerably less expensive shade structures, but these are permanent awnings or metallic roofs, which cannot be moved to accommodate different weather conditions. Essentially all of these prior art systems require the employment of a contractor or experienced installation professional in order to insure that they are properly installed. This, however, increases the cost of such units.
As a consequence, there is a need for a shade canopy structure which combines the features of being inexpensive, yet strong and sturdy, while also being sufficiently simple and easy to install that it can be installed by do-it-yourself home owners. There is also a need for a canopy which permits the user to tailor the shape and size of the shade area to accommodate the user's layout of furniture and other objects for any desired sun and weather conditions. There is also a need for a canopy shade structure which does not require custom manufacturing, but rather is capable of being constructed from standard components in multiple, modular units so that it can be inexpensively custom fit to essentially any size outdoor area of human habitation. There is also a need for a shade canopy structure which can be very simply and easily manually retracted or extended without requiring complicated mechanisms for winding the shade fabric on a roll and unwinding it.
The prior art illustrates a variety of door and window shading structures having spaced crossbars attached along a ribbon of fabric, with the crossbars sliding in a track on each side of the door or window. Such structures are shown, for example, in U.S. Pat. Nos. 4,647,488; 4,776,379; 5,379,823; and 5,503,210. These devices extend between opposite door sides, to span across a single opening required for a door.
U.S. Pat. No. 5,026,109 shows a similar concept applied to cover the cargo bin portion of a truck. That structure utilizes a rope and pulley mechanism for retracting and extending the cover. U.S. Pat. No. 1,713,452 shows similar concepts applied to a single window shade.
U.S. Pat. No. 1,106,624 shows a partial shade system for orchards which relies upon a plurality of side-by-side ribbons, each ribbon being an at least partially transparent fabric, which is supported by horizontally stretched ropes and rolled up on the ends. While this system allows a selectable contouring of the shaded area, it also requires rolling mechanisms and intermediate ropes to hold it down between the posts. Furthermore, its shade has intermittent, unshaded areas between the fabric ribbons and the tensioning of the support ropes causes the vertical posts to be pulled toward the center, and eventually become tilted in a non-vertical, unsightly orientation.